A memory device is an electronic device that stores information (data). There are various types of the memory devices, including semiconductor memory devices which may be largely classified into volatile memory and non-volatile memory devices. The volatile memory device retains data stored therein while powered on, but when the power is interrupted, the stored data is lost. In contrast, the non-volatile memory device maintains stored data even when power is turned off.
The non-volatile memory includes an OTP memory device. In an OTP memory device, a memory cell is driven by a write word line, a bit line, and a source line. A programming operation of the OTP memory cell may be performed by controlling the write word line, the bit line, and the source line differently. For example, a programmed cell may be applied with a voltage of about 5.5V to its source line, whilst an unprogrammed cell is applied with a voltage of about 1.5V to the source line. As such, it is necessary to arrange an additional source line to drive an OTP memory cell and a voltage of the source line should be controlled differently according to whether the cell is being programmed or not. However, if a cell array is programmed using various voltages, the cell may not be accurately programmed because of voltage mismatches. Also, there is difficulty in manufacturing an OTP cell array that requires multiple power lines routed therein.
Accordingly, there exists a need for an OTP memory device architecture that allows for efficient programming and driving of a plurality of OTP memory cells.